1. Field of the Invention
The present invention relates to a color electrophotographic image forming apparatus which uses a rotatable rotary supporting member (rotary) which supports a plurality of developing devices.
2. Description of the Related Art
Conventionally, there is known a color electrophotographic image forming apparatus which uses a rotatable rotary supporting member (rotary) which supports a plurality of developing devices. In the color electrophotographic image forming apparatus, there is known a construction in which a pulse motor is independently used as a motor for rotating the rotary supporting member (refer to Japanese Patent Application Laid-Open No. 2005-227719). The pulse motor is engaged with a gear of a large-diameter mounted to the rotary supporting member via multiple gears. By controlling the rotation of the pulse motor, the developing devices supported by the rotary supporting member are positively moved to the development position in which each of the developing devices faces the photosensitive drum.
As described above, in the conventional image forming apparatus, the stop position of the rotary supporting member is controlled by controlling a rotating speed of the pulse motor which can be controlled in its rotating speed. In addition, the pulse motor and the brushless motor which can be controlled in its rotating speed are expensive and large in size, thereby causing increases in cost and space of the apparatus.